Methods and systems that detect and differentiate epileptogenic from eloquent and normal cortices are provided. A method for identifying epileptogenic cortices in a brain may include detecting areas in the brain that are undergoing cerebral blood volume low frequency oscillations, detecting areas in the brain that are undergoing blood oxygenation low frequency oscillations; mapping clusters of the brain in which the cerebral blood volume low frequency oscillations are negatively correlated with the blood oxygenation low frequency oscillations, and analyzing the time based relationship between the clusters of the brain that are undergoing negatively correlated low frequency oscillations to determine cause areas, which are areas of the brain that are causing negatively correlated low frequency oscillations to occur elsewhere.